CustomEventHandler: Error writing request: The authentication or decryption has failed

I have a Unity C#/.NET app and a Java CustomEventHandler. I haven’t touched anything for a few years now and now I get the following error client side when trying to invoke the custom event handler:

Could not retreive FindLatestLessonBundleVersion info from backend:
Code = Internal client exception, Message = Error writing request: The authentication or decryption has failed.

Has anything changed in terms of updates to Backendless recently that may have made my old code incompatible?
Maybe I need to republish the server code using the latest versions?

Hi, @Simon_Nishi_McCorkindale

Please, provide us with you appId. It would also be helpful if you could provide an example of a simple code request that causes this error. Additionally, сould you describe which version of the .net Framework your program is using? Also which version of UnityPackage did you import? This will help us better understand the problem.

Regards, Marina

What is the secure way to let you know the app ID?

It’s a .NET Unity SDK I worked with Mark on many years ago before your official one, I can’t remember the exact .NET SDK version it was based on sorry and likewise, the code I don’t have on me right at the moment.

I wouldn’t be surprised if something got updated on your end that has now made it incompatible, hence the reason for asking if there were any major changes recently.


@Simon_Nishi_McCorkindale, perhaps the only thing that could break the work of your application is updating the version of the certificate on the server. Now only TLS 1.2 and TLS 1.3 are supported. If you update the .NET framework to a more recent version, or add support for certificates, the problem goes away.

Passing APP ID is safe, you only need to avoid publishing API keys

Best regards, Nikita.

Hi, thank you.
That might be it. It is a pretty old version.

The app id is 8F838470-81D7-5AF7-FFA7-D05FB7029300.